1. Technical Field of the Invention
The present invention relates to novel cosmetic and/or dermatological compositions (hereinafter sometimes xe2x80x9cantisunxe2x80x9d or xe2x80x9csunscreenxe2x80x9d compositions) for the photoprocection of the skin and/or the hair against UV radiation, in particular solar radiation. More especially, this invention relates to novel cosmetic and/or dermatological compositions exhibiting improved photostability and including, in a cosmetically and/or dermatologically acceptable substrate (vehicle, diluent or carrier), the combination of three specific screening agents.
The present invention also relates to the use of the subject compositions in the cosmetic and/or dermatological fields.
2. Description of the Prior Art
It is known to this art that light radiation of wavelengths of from 280 nm to 400 nm permits the human epidermis to tan and that irradiation of wavelengths of from 280 nm to 320 nm, i.e., UV-B irradiation, causes erythemas and skin burns which can be harmful to the development of the natural tan; hence, this UV-B radiation must therefore be screened from the skin.
It is also known to this art that UV-A radiation, of wavelengths of from 320 nm to 400 nm, which promotes tanning of the skin, also adversely affects it, especially in the case of a sensitive skin or of a skin which is continually exposed to solar radiation. UV-A rays cause, in particular, a loss in the elasticity of the skin and the appearance of wrinkles, promoting a premature aging thereof. Such irradiation promotes triggering of the erythematous reaction or amplifies this reaction in certain individuals and may even be the source of phototoxic or photoallergic reactions. It is therefore desirable to also filter or screen out the UV-A radiation.
Thus, for purposes of ensuring protection of the skin and of the hair against all of the UV radiation which is as complete as possible and as efficacious as possible, combinations of screening agents which are active in the UV-A region and of screening agents which are active in the UV-B region are typically employed in the formulation of sunscreen compositions.
In this respect, 4-tert-butyl-4xe2x80x2-methoxydibenzoylmethane, marketed under the trademark xe2x80x9cParsol 1789xe2x80x9d by Givaudan is a particularly advantageous screening agent active in the UV-A region, taking account of its high intrinsic absorptivity.
Similarly, 1,3,5-triazine derivatives and in particular, 2,4,6-tris[p-(2xe2x80x2-ethylhexyl-1xe2x80x2-oxycarbonyl)anilino]-1,3,5-triazine, marketed under the trademark xe2x80x9cUvinul T 150xe2x80x9d by BASF, have a high absorptivity for UV-B radiation. Therefore, it would be very advantageous to employ same in combination with the aforementioned 4-tert-butyl-4xe2x80x2-methoxydibenzoylmethane with a view towards providing products offering wide and efficacious protection throughout the entire range of UV radiation.
However, it has now been demonstrated that in the presence of 4-tert-butyl-4xe2x80x2-methoxydibenzoylmethane and under UV irradiation, the aforesaid 1,3,5-triazine derivatives present the disadvantage of being extensively degraded chemically. Under these conditions, the combination of the two screening agents no longer provides a prolonged broad protection of the skin and of the hair against solar radiation.
It has now unexpectedly been determined that the formulation of an alkyl xcex2,xcex2xe2x80x2-diphenylacrylate or is alkyl xcex1-cyano-xcex2,xcex2xe2x80x2-diohenylacrylate into compositions containing 4-tert-butyl-4xe2x80x2-methoxydibenzoylmethane in combination with at least one 1,3,5-triazine derivative, and in particular with 2,4,6-tris[p-(2xe2x80x2-ethylhexyl-1xe2x80x2-oxycarbonyl)anilino]-1,3,5-triazine, markedly enhances the stability of such at least one 1,3,5-triazine derivative within such compositions, and hence markedly enhances the overall effectiveness of these compositions.
Briefly, the present invention features novel cosmetic and/or dermatological compositions comprising, in a cosmetically and/or dermatologically acceptable carrier, diluent or vehicle, (i) 4-tert-butyl-4xe2x80x2-methoxydibenzoylmethane, (ii) at least one 1,3,5-triazine compound having the following structural formula (I): 
wherein X2 and X3, which may be identical or different, are each an oxygen atom or the xe2x80x94NHxe2x80x94 radical; and R1, R2 and R3, which may be identical or different, are each a hydrogen atom, an alkali metal, an ammonium radical optionally substituted by one or more alkyl or hydroxyalkyl radicals, a linear or branched C1-C18 alkyl radical, a C5-C12 cycloalkyl radical optionally ask substituted by one or more C1-C4 alkyl radicals, a polyoxyethylenated radical having from 1 to 6 ethylene oxide units and in which the terminal OH group is methylated, or a radical of the following formulae (II), (III) and (IV); 
wherein R4 is hydrogen or a methyl radical, R5 is a C1-C9 alkyl radical, n is an integer ranging from 0 to 3, m is an integer ranging from 1 to 10, A is a C4-C8 alkyl radical or a C5-C9 cycloalkyl radical, B is a linear or branched C1-C9 alkyl radical, a C5-C8 cycloalkyl radical, or an aryl radical optionally substituted by one or more C1-C4 alkyl radicals, and R6 is hydrogen or a methyl radical, and (iii) at least one alkyl xcex2,xcex2xe2x80x2-diphenylacrylate or alkyl xcex1-cyano-xcex2,xcex2xe2x80x2-diphenylacrylate having the following structural formula (V): 
in which R7 and Rxe2x80x27, which may be identical or different, are in a meta- or para-position and are each a hydrogen atom, a straight or branched chain C1-C8 alkoxy radical, or a straight or branched chain C1-C4 alkyl radical; R8 is a straight or branched chain C1-C12 alkyl radical; and R9 is a hydrogen atom or a xe2x80x94CN radical, with the proviso that said compositions are devoid of 2-ethylhexyl p-methoxycinnamate.